Silver bromoiodide photographic emulsion with improved green sensitivity

ABSTRACT

In a silver bromoiodide photographic emulsion containing at least one green sensitizing dye, a silver bromoiodide photographic emulsion wherein at least 0.01 mol percent of iodide ion based on silver halide adsorbs on the surface of silver bromoiodide grains contained in the emulsion.

United States Patent 11 1 1111 3,864,134 Ueda et al. Feb. 4, 1975 [541 SILVER BROMOIODIDE PHOTOGRAPHIC 3,436,221 4/1969 Sprung 96/108 ION WITH MPROVED GREEN 3,457,072 7/1969 Ditzer et a1. .1 96/94 R 3,531,288 9/1970 Jones 96/108 SENSITIVITY 3,594,172 7/1971 Sincius 96/108 [75] Inventors: Hirozo Ueda; Keisuke Shiba; Akira 3,745,015 7/1973 Van Pee et a1. 96/108 Sato, all of Kanagawa, Japan [73] Assignee: Photohl' ilfi Co., Ltd.) Minami Primary Examiner j Travis Brown S anagawa apan Attorney, Agent, or FirmSughrue, Rothwell, Mion, [22] Filed: Oct. 30, 1972 Zinn & Macpeak [21] Appl. No.: 301,912

[30] Foreign Application Priority Data [57] ABSTRACT Oct. 28, 1971 Japan 46-85835 In a silver bromoiodide photographic emulsion con- [52] US Cl 96/124, 96/108, 96/125, taining at least one green sensitizing dye, a silver bro- 96/137 moiodide photographic emulsion wherein at least 0.01 [51] Int. Cl G03c l/14, G03c 1/18 mol percent of iodide ion based on silver halide ad- [58] Field of Search 96/137, 124, 108, 125 sorbs 0n the surface of silver bromoiodide grains contained in the emulsion. [56] References Cited UNITED STATES PATENTS 4/1965 Fix 96/108 32 Claims, No Drawings SILVER BROMOIODIDE PHOTOGRAPHIC EMULSION WITH IMPROVED GREEN SENSITIVITY BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver bromoiodide emulsion comprising crystalline grains containing mixed crystals of silver bromoiodide having iodide ions and one or more sensitizing dyes absorbed on the surface thereof and, more particularly. it relates to an improved silver bromoiodide photographic emulsion suitable for spectral sensitization to green light.

2. Description of the Prior Art In the photographic emulsion-producing art, it has heretofore been well known that the spectral sensitivity of a photographic emulsion can be extended from the spectral sensitivity intrinsic to the silver halide (mainly ranging from the near ultraviolet region to the blue light region) to visible light of longer wavelengths or to the infrared region by the addition of dyes of the cyanine series to the photographic emulsion. This procedure is termed spectral sensitization.

The above-described procedure has enabled the art to markedly increase the usefulness of photographic materials utilizing silver halides as a light-sensitive element. Especially from the viewpoint of practical usage, spectral sensitization gives the silver halide a good parallelism with the spectral response of human eyes, and this produces a good reproduction of natural colors with a silver halide system. Moreover, the development of scientific uses such as infrared detectors and the like were also made possible.

A variety of combinations of dyes and photographic emulsions have been developed in order to use the above-mentioned spectral sensitization, depending on the purpose of the particular photographic lightsensitive material. The dye/emulsion combination is the main factor that determines in which spectral region the emulsion is sensitized, and how much sensitivity the emulsion is provided. Furthermore, a number of inventions have been made to improve the emulsions with respect to other desirable characteristics such as rapid processing capability, good storage capability of the light-sensitive material and latent images thereon, lowered color stain in the processed light-sensitive materials and the like, by the use of a specific dye/emulsion combination.

However, in spite of extensive investigation no completely satisfactory dye/emulsion combination has been proposed which satisfies all of the above factors for a specific emulsion.

For example, in the case of recording a green object, a difficulty arises from the fact that the main spectral reflection region of the green of the leaves of natural plants usually lies at about 550 nm, while the main spectral reflection region ofartificial green (such as the green of artificial plants, e.g., Hung-Kong flowers, and that of different types of printed material) lies in the range of from 510 to 530 nm. In practice, it is not always easy to provide a photographic emulsion with a spectral sensitivity capable of obtaining a good reproduction of both greens at the same time.

In addition, in the case of designing a lightsensitive material for color prints, it is often necessary to adjust the spectral sensitivity or the light-sensitivity of the light-sensitive material for duplication or printing within a range of from about 5 to about 10 nm, according to the spectral absorption region of the dyes used in the original color photographic image. However, this is not necessarily a simple matter either, as when the spectral absorption region is shifted to a desired region by slight modification of the chemical structure of the spectrally sensitizing dyes in order to shift the spectral sensitivity by only about 5 20 nm, accompanying difficulties often occur, e.g., the sensitivity is greatly changed. the rate of development is changed. the storage property is affected. color stain left on the processed material is visually increased. etc.

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a silver halide photographic emulsion capable of markedly improving the above-described difficulties, more specifically, an object of the present invention is to provide a photographic emulsion in a gelatino-silver bromoiodide photographic light-sensitive material wherein spectral sensitization in the green region is provided in a desired spectral wavelength region with- DETAILED DESCRIPTION OF THE INVENTION It could not have been expected from the prior art that the spectral sensitivity region could be precisely adjusted as desired without encountering the aforesaid difficulties, i.e., changes in sensitivity, etc., as described above.

It is a remarkable technical progress that the present invention makes it extremely easy to design a lightsensitive material according to the desired end use of the element.

In a silver bromoiodide emulsion, iodide ions are, of course, included in the grains as a mixed crystal, and hence it would naturally be supposed that a certain amount of iodide ions exist on the surface of the grains. It is therefore a surprising discovery that, in spite of the above fact, a certain addition amount of iodide ions provides marked effects from the viewpoint of spectral sensitization.

In general, it has been known that iodide ions can sometimes be added accidentally to a photographic emulsion together with spectral sensitizing dyes. That is, many of the cyanine dyes frequently employed as spectral sensitizing dyes are cationic dyes, and when these dyes have an iodide ion as a counter ion, iodide ions are added to the photographic emulsion together with the dye cations without any intention of doing such, and they sometimes adsorb on the silver halide grains. However, the molar amount of iodide ions added in such a situation is equal to that of the dye(s) added (That is, conventionally, this amount is very small, as compared with that of the present invention.

so that the effect obtained by adjusting the iodide ion amount added as described in the present invention is not shown.

The spectral sensitizing dyes used in the present invention are known, for example, they are described in Japanese Pat. publication No. 22884/68. West German Pat. OLS No. 2,030,326. etc.

it is described in Japanese Pat. publication No. 22884/68 that spectral sensitivity can be changed by altering the characteristics of the emulsion, above all, by a change in the silver ion concentration. It is true that the adsorption of iodide ions will naturally cause some change in the silver ion concentration. but the effect of the adsorbed iodide ions in a silver bromoiodide system could not be expected from prior art as described above. ln addition, the present invention tends in the direction of reducing the silver ion concentration, which is quite opposite to the direction of increasing the silver ion concentration to raise the spectral sensitivity as is described in the known literature cited above.

The procedure of preparing the photographic emulsion of the present invention having high green sensitivity will be more specifically described below.

The silver halide photographic emulsion contains silver bromoiodide mixed crystals preferably containing about 0.5 to about mol percent of iodide ions and, as a protective hydrophillic colloid, a major proportion of gelatin. Other protective colloid conventionally used in the art, such as phthalated gelatin, polyacrylic amide, polyvinylalcohol, polyvinylpyrrolidone, may be used, of course. Generally the ratio of silver iodobromide to protective colloid is from about 3:1 to about 1:3, by weight. This is not overly critical, however, and greater and lesser proportions can be used.

The mean grain size ofthe silver bromoiodide usually ranges from 0.2 to 2 3 p. in diameter, of course, finer or larger grain size silver halide may be used in the present invention. (refer, for example, to Trivelli Smith Emperical relations between sensitometric size frequency characterized in photographic series, Photographic Journal" vol LXXIX page 330 338( I939)) These grains are usually subjected to various sensitizing processes usually known as chemical ripening (such as sulfur sensitization, noble metal sensitization, reduction sensitization and the like).

The iodide ions are usually added to the system as a water-soluble iodide ion compound, generally added to the silver bromoiodide photographic emulsion sol in the form of an aqueous solution. The water-soluble iodide ion compound is prefered to be completely soluble or substantially soluble in water. The term watersoluble implies at least 10 weight percent solubility as a practical matter. As the water-soluble iodide ion compounds, there can be illustrated salts, for example, alkali metal salts such as sodium iodide and potassium iodide; Col amine salts such as ammonium iodide; and alkali earth metal such as Znl Cdl Cal Srl and Bal The proportion of iodide ions added, based on the silver bromoiodide, is at least 0.01 mol percent and preferably no more than l.0 mol percent, most preferably 0.05 to 0.3 mol percent, which is suitably adjusted depending upon the kind of the sensitizing dye and emulsion.

Alternatively, an iodide ion compound and a bromide ion compound (the molar ratio Br/l is operable in a range of from I to 30) may be mixed to form an aqueous solution, and added to a sol-state silver bromoiodide emulsion. This concentration of iodide and/or bromide is in addition to any bromide or iodide present throughout the grains as mixed silver halide. This procedure may give more reproduceable results with the invention than the single addition of iodide.

The aqueous solution containing iodide ions is added to the emulsion and sufficiently stirred. Substantially all of the iodide ions added are believed to immediately absorb on the silver bromoiodide grains. This is easily recognized by an immediate change in color of the grains.

To the resulting silver bromoiodide photographic emulsion (maintained in the sol state) to which iodide ions have been added there is added an organic solution of a spectral sensitizing dye which provides green sensitivity. Generally from about 10" to about 2 X 10 moles of green sensitizing dye (or dyes) is added per mole of silver halide. Use of a substantially lesser amount may provide lessened effects, whereas no overly significant increase is encountered by using substantially greater amounts.

The term green sensitizing dye" includes both an anionic dye and a cationic dye with or without an iodide ion as a counter anion.

As the green sensitizing dye used in the present invention, cyanine dyes comprising an oxacarbocyanine skeleton, such as benzoxacarbocyanine, naphthoxacarbocyanine, etc. [group I], cyanine dyes comprising a benzimidazolocarbocyanine skeleton, a henzimidazoloxacarbocyanine skeleton or a benzimidazoloindocarbocyanine skeleton, such as benzimidazolonaphthoxacarbocyanine, etc. [group ll], are preferably used, either independently or in combinations of at least two dyes wherein one belongs to group I and one belongs to group II, or at least two dyes belonging to group ll may be used. As used herein and in the appended claims, the term cyanine includes cyanine dyes and merocyanine dyes, e.g., monomethine cyanine dyes and carbocyanine dyes. As is well know from the article by Mees and James (The Theory of Photographic Process, llled, 1966, pp. 201 202), cyanine dyes feature the amidinium ion chromophore system wherein each nitrogen atom is contained in a beterocyclic ring.

Illustrating the above in even more detail, preferably dyes represented by the following general formula (I) are used among the dyes belonging to group (I):

2 g 2' /CII= CH: 5 3 1 5 and A and A and A,. can be the atoms necessary to form a benzene nucleus (in this case. the heterocyclic leg. acetoxy group. etc. alkoxycarhonyl group (cg. methoxycarbonyl. ethoxycarbonyl. propoxycarlmnyl. butoxycarbonyl group. etc.). carboxyl group. alkoxy group (e.g.. methoxy. ethoxy group. etc.). aryl group nucleus results in. for example, an a-naphthoxazole nu- 5 (eg. phenyl. tolyl group. etc.). cyano group. carbamcleus. B.B-naphthoxazole nucleus, or B-naphthoxazole oyl group (carbamoyl. methylcarbamoyl. phenylcarnucleus), R represents a hydrogen atom. lower alkyl bamoyl. dimethylcarbamoyl. diethylcarbamoyl. morgroup (e.g., methyl. ethyl, n-propyl group. etc.), aryl pholinocarbamoyl, piperidinocarbamoyl group. etc), group (eg. phenyl, tolyl group. etc.) etc. R and R alkylsulfonyl group (e.g.. methylsulfonyl group. etc.). each represents an alkyl group (such as methyl. ethyl, ll! alkylaminosulfonyl group (e.g.. methylaminosulfonyl. n-propyl group), hydroxyalkyl group (e.g.. 2- ethylaminosulfonyl. dimethylaminosulfonyl. morhydroxyethyl. 3-hydroxypropyl, 4-hydroxybutyl group. pholinosulfonyl, piperidinosulfonyl. pyrrolidinosult'oetc.), acetoxyalkyl group (e.g.. Z-acetoxyethyl. 3- nyl group. etc.) or aminosulfonyl group, or, when taken acetoxypropyl, 4-acetoxybutyl group, etc.), alkoxyaltogether, B and B can represent the atoms necessary kyl group (e.g., 2'methoxyethyl, B-methoxypropyl to form a bengene ring. Y represe ts group, etc.). alkyl group containing a carboxyl group (e.g., carboxymethyl, 2carboxyethyl, 3-carboxypropyl, 4-carboxybutyl, 2-(2-carboxyethoxy)ethyl group, etc.). an alkyl group containing a sulfo group (e.g.. 2- 8 sulfoethyl 3 Sulfompy] 4 sulfobutyl, wherein R and R each represents an alkyl group (e.g.. sulfopropyl. 2-(3-sulfopropoxy)ethyl, 2-acetoxy-3- methyL ethyl vmylmethyl group sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl. 2- [2-(3-sulfopropoxy)-ethoxy]ethyl, p-sulfobenzyl. p- -M sulfophenethyl group, etc.), benzyl group. phenethyl group. vinyl-methyl group, and the like. X represents wherein R represents an alkyl group (such as a methylan acid anion (e.g.. chloride, bromine. iodide. thiocyaethyl group). 3. R4 and s represent the Same alkyl nate. methylsulfate, ethyl-sulfate, perchlorate. p-tolgroups as R or R 0 represents a y rog n a m r uenesulfonate ion, etc), and n represents l or 2. In the s and R6 m y Combine ith each other through an alabove formula, A,, A A A R, R and R may be the kylene group (e.g.. dimethylene. trimethylene group. Same or diff t f h m etc.) (R often represents an alkylene group in the henof the dyes belonging to group ([1), those rePrezimidazoloindocarbocyanine dyes), and m represents] sented by the following general formula (2) are preferor the above general formula 1- a. a b d; R R R and R may he the same or different from H each other. I, Specific examples of dyes used in the present inven- 7 N Y 7' Ba tion are illustrated hereinafter. which in no way should 1 2 y be taken to limit the invention. (2) /-(7II::ClI--(IJ= TABLE I MX' 40 B2 4 I f Examples of dyes belonging to those represented by R4 R5 (X general formula (l) are:

Dye No. A1 A2 A3 Ar R R1 R: X 11 bootn goocm ir gi ii 5-F II 5'F C2I'I5 (CIIzhS a (CH2)3S03II 1 5-Br 11 5-Br c2115 (CIIQMSOF (owns/oat 1 s-oom n 500113 02H, (ottaaso (0119380311 1 5-CH3 II 5'-C IIa C2II5 (CI'IZ)ZSO3 (CII'J 3SO3II I .II 'C2II5 C2II5 (CII2)3SO3 (OH2)3S03II 1 (The numbers on the left side in the columns A and A represent the position of the substituent.)

TABLE 2 Examples of dyes belonging to those represented by the general formula (2) are:

sired photographic light-sensitive material.

TABLE 2 Continued Dye No. B B B3 B4 R1; R4 R; R m

5-C1 6'-Cl 5-Cl Cal-I I C211 C211 H NC2H SCN- 16 6-01 5-Cl El -CH3 6 T]: C2115 (011:)3803 GIL; C11 a 1 The numeral on the left side in the columns 8,, B2. Davis-Gibson filter) under an illuminance of 100 lux at B and B represents the position of the substituent.

As is described above, iodide ions and the green sensitizing dyes are added to a sol-state photographic emulsion to adsorb them onto the surface of the silver the exposure surface for 1/100 second through a yellow filter and a neutral continuous wedge, the yellow filter cutting blue light and thus enabling one to measure only the sensitivity of the spectrally sensitized region.

bromoiodide grains contained therein. The molar ratio 15 The exposed samples were developed in the followof a water-soluble iodide to a green sensitizing dye ing developer at C for 6 minutes. added is preferred to be within a range of from more Developer Composition: than 1 to about 6. The green sensitizing dye employed is preferably a dye without an iodide counter anion Monol (Trade name used by Fuji Photo Film when the ratio is near 1. After further adding to this 20 g ih' g for N'mcthyl'p'um'nophcnyl g emulsion other known additives for photographic Sodium SLllfilt: (anhydrous) 50g emulsions (such as stabilizers, hardeners, coating aids, g i f I g odlum carbonate (monohydrutc) 35 g.und and the like), the sol-state photographic emulsion is appotassium bromide 3 g plied to a support film comprising cellulose triacetate,

. Added successively to 1 liter of water.

polyethylene terephthalate, etc., at a uniform thickness, set with cold air and then dried by blowing a large amount of air with low moisture and at high temperature over the film. Thus, there can be obtained the de- EXAMPLE 1 A negative-working photographic emulsion comprising silver bromoiodide grains having a mean grain diameter of 0.7 u and containing 7.1 mol percent of 10- Immediately after the development. the materials were processed in a stopping bath (0.3 percent glacial acetic acid soln.), then in a fixing bath (Kodak F-5 solution; Kodak" is a registered trade mark), washed and dried. The optical density of the silver image formed was measured, and the sensitivity was determined from the reciprocal of the exposure required to obtain an optical density of 0.5 above fog. The results obtained are shown in Table 4.

Table 4 Sample No. 1 ll [11 1V V VI VII VIII Sensitivity 100* 145 160 160 200 225 200 320 Peak wavelength (my) 550 550 550 550 550 550 565 565 Taken as 100 as a standard for comparison convenience.

dide ion (based on the amount of silver ion) and gelatin (grains/gelatin 1.18 wt. ratio) was kept in a sol-state at C. To this emulsion were added the solutions of potassium iodide and the green sensitizing dye(s) each in an amount as is given in Table 3 to adsorb the same on said grains.

The addition of potassium iodide in an amount of more than 100 mg did not further increase the sensitivity. On the contrary, development was delayed by such addition.

As can be seen in the above Table, in the region wherein a significant increase in sesitivity cannot be ex- (All of the amounts added are per 1 mol of silver) Added as a 0.17: aqueous solution. Added as a 11.1% methanol solution.

The resulting emulsions (sol state) were applied on to a cellulose triacetate film base in a coating amount of 15 mg of silver/dm to a thickness of 5 #(after drying), and then dried.

The materials thus obtained were exposed to light of 4.800K (a tungsten lamp provided with a prescribed pected by increasing the amount of the dye (1) added, a further increase in sensitivity can be obtained by using potassium iodide together with the dye(s). In addition, in this case, the suitable amount lies between 50 and mg of potassium iodide per mol of silver.

It can also be seen that for the combination of dye (l) and dye l3 potassium iodide is similarly effective for sensitization. This combination gives green sensitivity of an approximately 15 mp. longer peak wavelength than that obtained by the use of dye l, but the speed (after drying) of u to the same support as in Example 1 which had been coated with an antihalation layer comprising 1.4 mg/dm of of colloidal silver particales dispersed in 2.14 g/m of gelatin and a red sensitive is kept equal between the two by the addition of an ap- 5 layer (containing 0.8 g/m of N-n-dodecyl-l-hydroxypropriate amount of iodide according to the invention, Z-naphthoic acid amide as a cyan coupler, 1.2 g/m of as seen from the comparison of sample V and VII in silver as silver iodobromide grains and red sensitizing Table 3 and 4 above. Such a dye combination is andye as the major constituents of this layer). other embodiment of the present invention. Onto the resulting green sensitive layer were applied successively a colloidal silver yellow filter layer, a blue EXAMPLE sensitive layer (containing 4-dodecyl-benzoyl-2- Dyes given in Table 5 were added to the same silver methoxy-acetanilide yellow coupler), and a protective bromoiodide photographic emulsion as in Example 1. film layer to obtain a color light-sensitive material. In this example, the amount of potassium iodide added The sensitivity of the light-sensitive material thus obwas fixed. The sensitivity of each of these samples 21 tained was measured in the same manner as in Example measured in the same manner as in Example 1 to obtain 1 except for the following procedure: the yellow filter the results given in Table 5. was not employed in the exposure and therefore the Table 5 Sample No. 1X X Xl Xll Xlll XIV XV XVI XVll XVlll Addeddye No. (3) (2) (3) (3) (4) (4) (5) (5) (6) (6) and the amount 200mg 200mg 200mg 200mg 200mg 200mg 200mg 200mg 200mg 200mg Amount of potassium iodide added 115mg 115mg 85mg 85mg 85mg Sensitivity" um 35 40 35 140 2 32 Peak wavelength (Amounts added are per 1 mol of silver) The sensitivity of sample No. l is taken as 100.

EXAMPLE 3 light-sensitive material was directly exposed to the light 0 An example of applying the photographic emulsion source of 4.800 K. To the developer there was further I added 1.5 g (per liter) of potassium thiocyanate, and of the invention to a green sensitive layer of a color 0 development was conducted at 24 C for 10 minutes. lightsensitive material is shown below. Aft d I t th ht t a] The same silver bromoiodide gelatin emulsions as in 35 er g L a we i s Example 1 were maintained at 35C in a sol state, and processe S oppnlg an Su expose to a strong diffuse white light over the entire surface to potassium iodide and the green sensitizing dye(s) were f I og the material. Thereafter, color development was added thereto as a percent aqueous solution and A conducted at 24C for 15 minutes in the followin col )1 0.1 percent methanol solution, respectively, each in an d velo r to btai a CO] I g 1 amount as given in Table 6. Thereafter, the resulting 40 pe o P C emulsions were left for 30 minutes while stirring so as omposl 0 e 0 or eve Oper' to adsorb the iodide and dye(s) sufficiently on the surface of the grains. Then, the following additives (per 1 BMW] alcohol in m mol of silver) were added thereto successively: ml Sodium sulfite (anhydrqus) 5.0g of a 0.5 percent aqueous solution of 5-methyl-7- 45 hl'drlllcl gg hydroxy-l,3-4-triazaindolizine as a stabilizer; g of gumsium,bmmidc ()5 g l-( 2,4.6-trichloro)-phenyl-3-dodecylamido-5- 22:12am" g gl pyrazolone (as a magenta coupler) dissolved in mixture WAmimxi.clhy|.My.nmhmmumm. Of 70 g of U'lCI'BSyl phosphate and 101) ml Of ethyl aceamidoethyLm-toluidiiie siill'onalu 10.5 g tate under heating and subsequently dispersed in 700 50 D g ofa 10 weight percent gelatin aqueous solution in the were added successively P 1 of water presence of 84 ml ofa 5 percent sodium dodecylsulfate Subsequen ly,,wa ing. bleaching, fixing and as ng aqueous solution;20 ml ofa 2 percent aqueous solution were conducted to obtain a Color image h Optical f2 6 di h] 4 hydr xy-triazjne; d 3 1 f 4 density of the magenta image therein were measured cent aqueous solution of saponin. 55 through a green filter, which was represented by the re- The resulting photographic emulsion was applied to clprocal of the exposure providing a density of 0.5. The provide an amount of silver of 18 mg/dm to a thickness results obtained are given in the following Table.

Table 6 Sample No. XlX XX XX] XX" XXlll XXIV XXV XXVI XXVll XXVlll XXIX XXX XXX] XXX" Eye (1) (l) (2) (2) (4) 1 (8) (8) (l0) 2) 0. and the 200 200 200 200 (12) 200 200 200 200 200 200 200 200 20a amount mg mg mg mg mg mg mg m m m' m m m m thereof (13] (l3) (l3) (l3) (l3) (l3) (l3) (1%) L -L' added 50mg 50mg 50mg illmg 50mg 50mg 50mg 50mg 85mg 85mg 85mg 85mg M 1 5mg liSnig 85mg Table 6 Continued Sample No, XXlll XIX XX XXl XXll (per 1 mol of silver) I00 taken as the standard.

xxiv xxv XXVI XXVll XXVlll XXIX XXX XXX] XXX 560 555 555 560 Slit) From Table 6 above, the excellent effect of the present invention can he understood to he provided similarly to the case of Example 2.

EXAMPLE 4 The same silver bromoiodide photographic emulsion as in Example I was maintained in a sol state at 35C. and an aqueous solution of potassium iodide and a methanol solution of dye(s) were added thereto as shown in Table 7 to adsorb the dye(s) and iodide onto the grains. The resulting emulsions were applied and dried in the same manner as in Example I, and subsequently subjected to sensitometry measurements to thereby obtain the sensitivity data shown in the following Table. In the case of using these dyes too. the same effect of potassium iodide as was illustrated in the foregoing Examples can clearly be recognized.

Table 7 Sample No. XXXlll XXXlV XXXV XXXVI XXXVll Amount of potassium iodide added Amount of 200mg 200mg 200mg 50mg 50mg 50mg (Amounts added were per l mol ol'silver) IUII taken as the standard.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

What is claimed is:

1. In a silver bromoiodide negative-working photographic emulsion of the developing out type which is subjected to only one exposure followed by wetdeveloping, said emulsion containing at least one green sensitizing dye to effect green sensitization thereof, a silver bromoiodide photographic emulsion wherein at least 0.01 mol percent of iodide ion based on silver halide adsorbs on the surface of silver bromoiodide grains contained in the emulsion. said iodide ion being in addition to iodine present in said silver iodobromide grains and said green sensitizing dye intensely sensitizing said emulsion to green without substantially deteriorating its photographic properties wherein said green sensitizing dye is represented by one of the following general formulae wherein A, and A,-, each represents a hydrogen atom or halogen atom. A and A, represent a hydrogen atom. halogen atom, hydroxy group. alkoxy group. amino group, acylamido group, acyloxy group, alkoxycar-.

wherein B, represents a hydrogen atom or halogen atom. B 8;, and B, each represents a hydrogen atom, halogen atom, lower alkyl group. amino group, acylamido group, acyloxy group, alkoxycarbonyl group, carboxyl group. alkoxy group, aryl group, cyano group, carbamoyl group. alkylsulfonyl group. alkylaminosulfonyl group or aminosulfonyl group, or. when taken together, 8,, and B, can represent the atoms necessary to form a benzene ring. Y represents O- wherein R and R each represents an alkyl group,

wherein R represents an alkyl group, R R and R represent the same alkyl groups as R or R R represents a hydrogen atom or R and R may combine with each other through an alkylene group. and m represents l or 2.

2. The photographic emulsion as claimed in claim 1, wherein bromide ion in an amount of from i to 30 times of the molar concentration of the iodide ion added is also adsorbed on the surface of silver bromoiodide grains contained in the emulsion.

3. The photographic emulsion as claimed in claim 1 comprising silver bromoiodide mixed crystals with about 0.01 to about 1.0 mol percent of iodide ions adsorbed on the surface thereof.

4. The photographic emulsion as claimed in claim 1, wherein the green sensitizing dye is an anionic dye.

5. The photographic emulsion as claimed in claim 1, wherein the green sensitizing dye is a cationic dye without an iodide ion as a counter anion.

6. The photographic emulsion as claimed in claim 1, wherein the amount of said iodide ions added is at least 0.05 mol percent based on silver halide and the green sensitizing dye is a cationic dye with an iodide ion as a counter anion.

7. The photographic emulsion as claimed in claim 1, wherein the amount of said iodide ions added is within the range of from 0.05 to 03 mol percent based on silver halide.

8. The photographic emulsion as claimed in claim 1, wherein at least two of said dyes are used in combina- Hon.

9. The photographic emulsion as claimed in claim 1, wherein the halogen atom in A,, A or B is chlorine, bromine, iodine or fluorine; wherein the alkoxy group is methoxy or ethoxy, the amino group is amino, methylamino or dimethylamino, the acylamido group is acetoamido or propionamido, the acyloxy group is acetoxy, the alkoxycarbonyl group is methoxycarbonyl, ethoxycarbonyl, propioxycarbonyl or butoxycarbonyl in A A B B or B the lower alkyl group is methyl, ethyl or isopropyl in A or A wherein the lower aklyl group is methyl, ethyl or n-propyl, and' the aryl group is phenyl or tolyl in R wherein the alkyl group is methyl, ethyl or n-propyl, the hydroxyalkyl group is 2- hydroxyethyl, 3-hydroxypropyl or 4-hydroxybutyl, the acetoxyalkyl group is Z-acetoxyethyl, 3-acetoxypropyl or 4-acetoxybutyl, the alkoxyalkyl group is 2- methoxyethyl or 3-methoxypropyl, the alkyl group containing 21 carboxy group is carboxymethyl, 2- carboxyethyl, 3-carboxypropyl, 4-carboxybutyl or 2-(2-carboxyethoxy)ethyl, the alkyl group containing a sulfo group is 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-3-sulfopropyl, 2-(3-sulfopropoxy) ethyl, 2-acetoxy-3-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-[2-(3-sulfopropoxy)-ethoxy]ethyl, psulfobenzyl, p-sulfobenzyl or p-sulfophenethyl in R R R R or R wherein the lower alkyl group is methyl, ethyl or trifluoromethyl, the aryl group is phenyl or tolyl, the carbamoyl group is carbamoyl, methylcarbamoyl, phenylcarbamoyl, dimethylcarbamoyl, diethylcarbamoyl, morpholinocarbamoyl or piperidinocarbamoyl, the alkyl sulfonyl group is methyl sulfonyl, the alkylaminosulfonyl group is methylaminosulfonyl, ethylaminosulfonyl, dimethylaminosulfonyl. morpholinosulfonyl, piperidinosulfonyl or pyrrolidinosulfonyl in B B or B wherein the alkyl group in R or R is methyl, ethyl or vinylmethyl; wherein the alkyl group is R, is methyl or ethyl; and wherein the alkylene group, which joins together R and R is dimethylene or trimethylene.

10. The photographic emulsion as claimed in claim 1, wherein said green sensitizing dye is a cyanine dye selected from the group:

0 e 0 -a=l-al c N a N a I]. The photographic emulsion as claimed in claim I. wherein more than one green sensitizing dye is used. the dyes comprising a combination of:

t q o v(c14 0) (cri so 2 )2( 2)3 3 12. The photographic emulsion as claimed in claim I, wherein the amount of green sensitizing dye is within the range of from 10' to 2 X 10 moles per 1 mole of silver halide.

13. The photographic emulsion as claimed in claim 1, wherein the emulsion comprises a hydrophilic colloid selected from the group gelatin, phthalated gelatin, polyacrylic amide, polyvinyl alcohol and polyvinyl pyrrolidone.

14. The photographic emulsion as claimed in claim 1, further containing a coupler.

15. The photographic light-sensitive silver halide material which comprises a support having thereon at least one layer comprising a photographic emulsion as claimed in claim 1.

16. In a process for spectrally sensitizing a negativeworking silver bromoiodide photographic emulsion of the developing out type which is subjected to only one exposure followed by wet-developing, said emulsion containing at least one green sensitizing dye which effects the green sensitization of said emulsion, the improvement comprising adsorbing at least0.l mol percent iodide ions on the surface of the silver halide grains in the emulsion, said iodide being in addition to iodine present in said silver iodobromide, whereby the emulsion is intensely sensitized to green without substantially deteriorating its photographic properties wherein said green sensitizing dye is represented by one of the following general formulae wherein A, and A, each represents a hydrogen atom or halogen atom, A and A, represent a hydrogen atom, halogen atom, hydroxy group, alkoxy group, amino group. acylamido group, acyloxy group, alkoxycarbonyl group, lower alkyl group or alkoxycarbonylamino group, or, when taken together, A, and A and A and A,, can be the atoms necessary to form a benzene nucleus, R respresents a hydrogen atom, lower alkyl group, or aryl group, R, and R each represents an alkyl group, hydroxyalkyl group, acetoxyalkyl group, alkoxyalkyl group, alkyl group containing a carboxyl group, alkyl group containing sulfo group, benzyl group, phenethyl group or a vinylmethyl group; and

wherein B, represents a hydrogen atom or halogen atom, B B and 8, each represents a hydrogen atom, halogen atom, lower alkyl group, amino group, acylamino group, acyloxy group, alkoxycarbonyl group, carboxyl group, alkoxy group, aryl group, cyano group, carbamoyl group, alkylsulfonyl group, alkylaminosulfonyl group or aminosulfonyl group, or, when taken together, B and B can represent the atoms necessary to form a benzene ring, Y represents O wherein R, and R,, each represents an alkyl group,

N-Ry,

wherein R represents an alkyl group, R;,, R, and R represent the same alkyl groups as R, or R R,, represents a hydrogen atom or R,-, and R may combine with each other through an alkylene group, and m represents l or 2.

17. The process as claimed in claim 16, wherein bromide ion in an amount of from l to 30 times of the molar concentration of the iodide ion added is also adsorbed on the surface of silver bromoiodide grains contained in the emulsion.

18. The process as claimed in claim 16, wherein said emulsion comprises silver bromoiodide mixed crystals with about 0.01 to about 1.0 mol percent of iodide ions adsorbed on the surface thereof.

19. The process as claimed in claim 16, wherein the amount of said iodide ions added is within the range of from 0.05 to 0.3 mol percent based on silver halide,

20. The process as claimed in claim 16, wherein at least two of said dyes are used in combination.

2]. The process as claimed in claim 16, wherein the halogen atom in A,, A, or B, is chlorine, bromine, iodine or fluorine; wherein the alkoxy group is methoxy or ethoxy, the amino group is amino, methylamino or dimethylamino, the acylamido group is acetoamido or propionamido; the acyloxy group is acetoxy, the alkoxycarbonyl group is methoxycarbonyl, ethoxycarbonyl, propioxycarbonyl or butoxycarbonyl in A A B 8,, or 8,; the lower alkyl group is methyl, ethyl or isopropyl in A or A wherein the lower alkyl group is methyl, ethyl or n-propyl, and the aryl group is phenyl or tolyl in R, wherein the alkyl group is methyl, ethyl or n-propyl, the hydroxyalkyl group is 2-hydroxyethyl, 3-hydroxypropyl or 4-hydroxybutyl, the acetoxyalkyl group is Z-acetoxyethyl, 3-acetoxypropyl or 4- acetoxybutyl, the alkoxyalkyl group is 2-methoxyethyl or 3-methoxypropyl. the alkyl group containing a carboxy group is carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl or 2-(2-carboxyethoxy)ethyl, the alkyl group containing a sulfo group is 2- sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-3- sulfopropyl, 2-(3-sulfopropoxy) ethyl, 2-acetoxy-3- sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2- [2-(3-sulfopropoxy)-ethoxylethyl, p-sulfobenzyl, psulfobenzyl or p-sulfophenethyl in R,. R R,,. R, or R,-,', wherein the lower alkyl group is methyl, ethyl or trifluoromethyl, the aryl group is phenyl or tolyl, the carbamoyl group is carbamoyl, methylcarbamoyl, phenylcarbamoyl, dismethylcarbamoyl, diethylcarbamoyl morpholinocarbamoyl or piperidinocarbamoyl, the alkyl sulfonyl group is methyl sulfonyl, the alkylaminosulfonyl group is methylaminosulfonyl, ethylaminosulfonyl, dimethylaminosulfonyl, morpholinosulfonyl, piperidinosulfonyl or pyrrolidinosulfonyl in B B or 8,; wherein the alkyl group in R, or R,, is methyl, ethyl or vinylmethyl; wherein the alkyl group in R,, is methyl or ethyl; and wherein the alkylene group, which joins together R, and R,,, is dimethylene or trimethylene.

22. The process as claimed in claim 16, wherein said green sensitizing dye is a cyanine dye selected from the group:

and

23. The process as claimed in claim 16, wherein more than one green sensitizing dye is used, the dyes comprising a combination of:

Calls (CI-I: 0)1(CH1)1S 03 (CH, omenms O N-a 24. The process as claimed in claim 16, wherein the amount of green sensitizing dye is within the range of from 10 to 2 X 10 moles per i mole ofsilver halide.

25. The photographic emulsion of claim 1 which has been chemically ripened.

26. The process of claim 16, wherein said photographic emulsion has been chemically ripened.

27. The photographic emulsion of claim 1, wherein more than 1 green sensitizing dye is used, the spectral absorption regions of the green sensitizing dyes differing from each other.

28. The process of claim 16, wherein more than 1 green sensitizing dye is used, the spectral absorption regions ofthe green sensitizing dyes differing from each other.

29. The photographic emulsion as claimed in claim 1 wherein said silver bromoiodide mixed crystals contain about 0.5 to about 10 mol percent of iodide ions based on the total silver halide.

30. The process as claimed in claim 16. wherein said silver bromoiodide mixed crystals used contain about 0.05 to about 10 mol percent of iodide ions based on the total silver halide.

31. The photographic emulsion as claimed in claim I wherein the green sensitizing dye is cationic.

32. The process as claimed in claim 16. wherein the green sensitizing dye is cationic. 

2. The photographic emulsion as claimed in claim 1, wherein bromide ion in an amount of from 1 to 30 times of the molar concentration of the iodide ion added is also adsorbed on the surface of silver bromoiodide grains contained in the emulsion.
 3. The photographic emulsion as claimed in claim 1 comprising silver bromoiodide mixed crystals with about 0.01 to about 1.0 mol percent of iodide ions adsorbed on the surface thereof.
 4. The photographic emulsion as claimed in claim 1, wherein the green sensitizing dye is an anionic dye.
 5. The photographic emulsion as claimed in claim 1, wherein the green sensitizing dye is a cationic dye without an iodide ion as a counter anion.
 6. The photographic emulsion as claimed in claim 1, wherein the amount of said iodide ions added is at least 0.05 mol percent based on silver halide and the green sensitizing dye is a cationic dye with an iodide ion as a counter anion.
 7. The photographic emulsion aS claimed in claim 1, wherein the amount of said iodide ions added is within the range of from 0.05 to 0.3 mol percent based on silver halide.
 8. The photographic emulsion as claimed in claim 1, wherein at least two of said dyes are used in combination.
 9. The photographic emulsion as claimed in claim 1, wherein the halogen atom in A1, A3 or B1 is chlorine, bromine, iodine or fluorine; wherein the alkoxy group is methoxy or ethoxy, the amino group is amino, methylamino or dimethylamino, the acylamido group is acetoamido or propionamido, the acyloxy group is acetoxy, the alkoxycarbonyl group is methoxycarbonyl, ethoxycarbonyl, propioxycarbonyl or butoxycarbonyl in A2, A4, B2, B3 or B4; the lower alkyl group is methyl, ethyl or isopropyl in A2 or A4; wherein the lower aklyl group is methyl, ethyl or n-propyl, and the aryl group is phenyl or tolyl in R4 wherein the alkyl group is methyl, ethyl or n-propyl, the hydroxyalkyl group is 2-hydroxyethyl, 3-hydroxypropyl or 4-hydroxybutyl, the acetoxyalkyl group is 2-acetoxyethyl, 3-acetoxypropyl or 4-acetoxybutyl, the alkoxyalkyl group is 2-methoxyethyl or 3-methoxypropyl, the alkyl group containing a carboxy group is carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl or 2-(2-carboxyethoxy)ethyl, the alkyl group containing a sulfo group is 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-3-sulfopropyl, 2-(3-sulfopropoxy) ethyl, 2-acetoxy-3-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-(2-(3-sulfopropoxy)-ethoxy) ethyl, p-sulfobenzyl, p-sulfobenzyl or p-sulfophenethyl in R1, R2, R3, R4 or R5; wherein the lower alkyl group is methyl, ethyl or trifluoromethyl, the aryl group is phenyl or tolyl, the carbamoyl group is carbamoyl, methylcarbamoyl, phenylcarbamoyl, dimethylcarbamoyl, diethylcarbamoyl, morpholinocarbamoyl or piperidinocarbamoyl, the alkyl sulfonyl group is methyl sulfonyl, the alkylaminosulfonyl group is methylaminosulfonyl, ethylaminosulfonyl, dimethylaminosulfonyl, morpholinosulfonyl, piperidinosulfonyl or pyrrolidinosulfonyl in B2, B3 or B4; wherein the alkyl group in R7 or R8 is methyl, ethyl or vinylmethyl; wherein the alkyl group is R9 is methyl or ethyl; and wherein the alkylene group, which joins together R5 and R6, is dimethylene or trimethylene.
 10. The photographic emulsion as claimed in claim 1, wherein said green sensitizing dye is a cyanine dye selected from the group:
 11. The photographic emulsion as claimed in claim 1, wherein more than one green sensitizing dye is used, the dyes comprising a combination of:
 12. The photographic emulsion as claimed in claim 1, wherein the amount of green sensitizing dye is within the range of from 10 4 to 2 X 10 2 moles per 1 mole of silver halide.
 13. The photographic emulsion as claimed in claim 1, wherein the emulsion comprises a hydrophilic colloid selected from the group gelatin, phthalated gelatin, polyacrylic amide, polyvinyl alcohol and polyvinyl pyrrolidone.
 14. The photographic emulsion as claimed in claim 1, further containing a coupler.
 15. The photographic light-sensitive silver halide material which comprises a support having thereon at least one layer comprising a photographic emulsion as claimed in claim
 1. 16. In a process for spectrally sensitizing a negative-working silver bromoiodide photographic emulsion of the developing out type which is subjected to only one exposure followed by wet-developing, said emulsion containing at least one green sensitizing dye which effects the green sensitization of said emulsion, the improvement comprising adsorbing at least 0.1 mol percent iodide ions on the surface of the silver halide grains in the emulsion, said iodide being in addition to iodine present in said silver iodobromide, whereby the emulsion is intensely sensitized to green without substantially deteriorating its photographic properties wherein said green sensitizing dye is represented by one of the following general formulae
 17. The process as claimed in claim 16, wherein bromide ion in an amount of from 1 to 30 times of the molar concentration of the iodide ion added is also adsorbed on the surface of silver bromoiodide grains contained in the emulsion.
 18. The process as claimed in claim 16, wherein said emulsion comprises silver bromoiodide mixed crystals with about 0.01 to about 1.0 mol percent of iodide ions adsorbed on the surface thereof.
 19. The process as claimed in claim 16, wherein the amount of said iodide ions added is within the range of from 0.05 to 0.3 mol percent based on silver halide.
 20. The process as claimed in claim 16, wherein at least two of said dyes are used in combination.
 21. The process as claimed in claim 16, wherein the halogen atom in A1, A3 or B1 is chlorine, bromine, iodine or fluorine; wherein the alkoxy group is methoxy or ethoxy, the amino group is amino, methylamino or dimethylamino, the acylamido group is acetoamido or propionamido; the acyloxy group is acetoxy, the alkoxycarbonyl group is methoxycarbonyl, ethoxycarbonyl, propioxycarbonyl or butoxycarbonyl in A2, A4, B2, B3 or B4; the lower alkyl group is methyl, ethyl or isopropyl in A2 or A4; wherein the lower alkyl group is methyl, ethyl or n-propyl, and the aryl group is phenyl or tolyl in R4 wherein the alkyl group is methyl, ethyl or n-propyl, the hydroxyalkyl group is 2-hydroxyethyl, 3-hydroxypropyl or 4-hydroxybutyl, the acetoxyalkyl group is 2-acetoxyethyl, 3-acetoxypropyl or 4-acetoxybutyl, the alkoxyalkyl group is 2-methoxyethyl or 3-methoxypropyl, the alkyl group containing a carboxy group is carboxymethyl, 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl or 2-(2-carboxyethoxy)ethyl, the alkyl group containing a sulfo group is 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl, 2-hydroxy-3-sulfopropyl, 2-(3-sulfopropoxy) ethyl, 2-acetoxy-3-sulfopropyl, 3-methoxy-2-(3-sulfopropoxy)propyl, 2-(2-(3-sulfopropoxy)-ethoxy) ethyl, p-sulfobenzyl, p-sulfobenzyl or p-sulfophenethyl in R1, R2, R3, R4 or R5; wherein the lower alkyl group is methyl, ethyl or trifluoromethyl, the aryl group is phenyl or tolyl, the carbamoyl group is carbamoyl, methylcarbamoyl, phenylcarbamoyl, dismethylcarbamoyl, diethylcarbamoyl morpholinocarbamoyl or piperidinocarbamoyl, the alkyl sulfonyl group is methyl sulfonyl, the alkylaminosulfonyl group is methylaminosulfonyl, ethylaminosulfonyl, dimethylaminosulfonyl, morpholinosulfonyl, piperidinosulfonyl or pyrrolidinosulfonyl in B2, B3 or B4; wherein the alkyl group in R7 or R8 is methyl, ethyl or vinylmethyl; wherein the alkyl group in R9 is methyl or ethyl; and wherein the alkylene group, which joins together R5 and R6, is dimethylene or trimethylene.
 22. The process as claimed in claim 16, wherein said green sensitizing dye is a cyanine dye selected from the group:
 23. The process as claimed in claim 16, wherein more than one green sensitizing dye is used, the dyes comprising a combination of:
 24. The process as claimed in claim 16, wherein the amount of green sensitizing dye is within the range of from 10 4 to 2 X 10 2 moles per 1 mole of silver halide.
 25. The photographic emulsion of claim 1 which has been chemically ripened.
 26. The process of claim 16, wherein said photographic emulsion has been chemically ripened.
 27. The photographic emulsion of claim 1, wherein more than 1 green sensitizing dye is used, the spectral absorption regions of the green sensitizing dyes differing from each other.
 28. The process of claim 16, wherein more than 1 green sensitizing dye is used, the spectral absorption regions of the green sensitizing dyes differing from each other.
 29. The photographic emulsion as claimed in claim 1 wherein said silver bromoiodide mixed crystals contain about 0.5 to about 10 mol percent of iodide ions based on the total silver halide.
 30. The process as claimed in claim 16, wherein said silver bromoiodide mixed crystals used contain about 0.05 to about 10 mol percent of iodide ions based on the total silver halide.
 31. The photographic emulsion as claimed in claim 1 wherein the green sensitizing dye is cationic.
 32. The process as claimed in claim 16, wherein the green sensitizing dye is cationic. 